Adjustable knife sharpener



FIG. 1 is a front, perspective view of an adjustable knife sharpener according to an embodiment of the invention.

FIG. 2 is a front view of the adjustable knife sharpener of FIG. 1.

FIG. 3 is a top view of the adjustable knife sharpener of FIG. 1.

FIG. 4 is a right side view of the adjustable knife sharpener of FIG. 1; and,

FIG. 5 is a rear view of the adjustable knife sharpener of FIG. 1.

The broken lines in the drawings illustrate features of the design that form no part of the claim. 

We claim the ornamental design for an adjustable knife sharpener, as shown. 